Purpose: African-Americans and Hispanics suffer from a disproportionate amount of cardiovascular mortality despite the former having lower cholesterol than Caucasians. Major risk factors for cardiovascular disease include hypertension (HTN), diabetes milletus (DM), and hypercholesterolemia. The purpose of this study was to assess whether there are racial/ethnic disparities in the association between having one or more of these conditions and inflammatory processes associated with plaque instability. This study examined racial/ethnic distributions in the relationship between HTN, hypercholesterolemia, DM and inflammatory markers interleukin-6 (IL-6), fibrinogen, and cardiac sensitive C-reactive protein (hsCRP).
Methods: A total of 571 participants were recruited from NorTex member clinics from April 2006 to June 2008. Participants underwent body measurements and lab analyses. Race/ethnicity was self-reported. Serum levels of IL-6, hsCRP, and fibrinogen were measured. Participants with hsCRP levels greater than 10 or reporting active infection were excluded, resulting in a final sample of 429. The independent variable grouped by ethnicity was chronic disease state which consisted of a composite score, summing diagnoses of HTN, high cholesterol, and DM. Variables of interest include IL-6, CRP, and fibrinogen.
Results: Of the 429 participants, 112 were white (25.7%), 155 were African American (35.6%), and 162 were Hispanic (37.2%). Of these, 111 had none of the three chronic diseases (25.5%), 156 had one of the three (35.9%), and 166 had 2-3 diseases (38.2%). African-Americans showed the most pronounced trend in mean CRP levels with increasing number of diseases, while Caucasian and Hispanic mean levels declined slightly. With mean IL-6 levels, Caucasians showed an increasing trend with disease while the other groups did not. Fibrinogen activity showed a slight increasing trend with disease for African-Americans and Caucasians, but not for Hispanics (See Table 2).
Conclusions: This is the first study to examine the number of chronic diseases and inflammatory markers. Our results revealed some ethnic differences in cardiovascular markers with an increasing number of chronic diseases. This warrants further investigation. Future studies will need to examine to what extent these differences contribute to cardiovascular mortality so appropriate treatments and their intensification can be developed. (Grant Number P20MD001633 from the National Center on Minority Health Disparities)